The present invention relates to a material usable for the electrodes and the dielectric layer of a plasma display panel, and to a plasma display panel using the material.
High-definition, thin and large-size plasma display panels (hereinafter, sometimes referred to as PDP) attract great attention in the fields of OA apparatuses, information displays and high-definition televisions.
Referring now to FIGS. 1 and 2, the display principle of a conventional PDP will be described. FIG. 1 is a schematic partial cross-sectional view of the surface side of the plasma display panel. FIG. 2 is a schematic partial cross-sectional view of the back side of the plasma display panel.
First, plasma is discharged between two display electrodes 3 provided on a surface glass substrate 1 serving as the display surface, thereby generating ultraviolet rays. Then, the ultraviolet rays excite a fluorescent substance 6 separated by partitions 9 on a back surface glass substrate 2, thereby generating visible light. The generated visible light passes through an MgO film 10, a surface dielectric layer 7 and the surface glass substrate 1 to be displayed as an image. This image display is performed by applying a signal to address electrodes 5 provided on the back surface glass substrate 2 and specifying which discharge cell to display. In this case, in the PDP, a plurality of linear electrodes is disposed in parallel on the surface glass substrate 1 and the back surface glass substrate 2, and the display electrodes 3 on the surface glass substrate 1 and the address electrodes 5 on the back surface glass substrate 2 are placed one on the other so that their linear electrodes are laid in the intersecting directions.
The display electrodes 3 on the surface glass substrate 1 are formed by applying a paste-like electrode material onto the substrate by a method such as screen printing, photolithography or a lift-off method and then, baking the material.
The surface dielectric layer 7 is provided for ensuring insulation between the electrodes and generating and maintaining plasma. The surface dielectric layer 7 is formed by applying a paste-like dielectric material onto the display electrodes 3 by a method such as screen printing, a bar coater method, a roll coater method, a blade coater method or a die coater method and then, drying and baking the material.
The back surface glass substrate 2 has the address electrodes 5 and a back surface dielectric layer 8 serving as the protective film for the address electrodes 5. These are formed in a similar manner to the case of the surface dielectric layer 7.
For this conventional PDP, Ag is used as the conductive metal contained in the electrodes (for example, Japanese Laid-Open Patent Publication No. H11-283508).
In this case, however, after baking is performed to obtain the electrodes, the dielectric layers and the MgO film, a phenomenon that the glass substrates or the dielectric layers are discolored yellow (yellowing) occurs, so that the image quality of the PDP is significantly degraded. In particular, the occurrence of yellowing in the surface glass substrate serving as the display surface is a serious problem. This problem is more serious for high-definition patterns of high-definition televisions and the like.
Accordingly, an object of the present invention is to solve the above-mentioned problem, that is, to provide a material usable for the electrodes and the dielectric layer of PDPs and capable of reducing the occurrence of yellowing, and a high-image-quality PDP using the material.
The present invention provides an electrode material for a plasma display panel, comprising:
Ag powder;
glass powder containing 25 to 50 wt % of Bi2O3, 5 to 35 wt % of B2O3, 10 to 20 wt % of ZnO, 5 to 20 wt % of BaO, 0 to 15 wt % of SiO2 and 0 to 10 wt % of Al2O3; and
an organic component containing a resin and a solvent.
In this case, it is preferable that the glass powder has an average grain size of not more than 4.0 xcexcm and a maximum grain size of not more than 10 xcexcm.
Moreover, the present invention provides a dielectric material for a plasma display panel, comprising:
glass powder containing 25 to 50 wt % of Bi2O3, 5 to 35 wt % of B2O3, 10 to 20 wt % of ZnO, 5 to 20 wt % of BaO, 0 to 15 wt % of SiO2 and 0 to 10 wt % of Al2O3; and
an organic component containing a resin and a solvent.
In this case, it is preferable that the glass powder contains 25 to 40 wt % of Bi2O3, 15 to 35 wt % of B2O3, 10 to 20 wt % of ZnO, 10 to 20 wt % of BaO, 0 to 10 wt % of SiO2 and 0 to 10 wt % of Al2O3.
Moreover, it is preferable that the glass powder further contains 0.1 to 2 wt % of CuO.
Further, the present invention provides a plasma display panel comprising:
a plurality of electrodes comprising a first glass and Ag; and
a dielectric layer comprising a second glass and insulating the electrodes from each other,
wherein at least one of the first glass and the second glass contains 25 to 50 wt % of Bi2O3, 5 to 35 wt % of B2O3, 10 to 20 wt % of ZnO, 5 to 20 wt % of BaO, 0 to 15 wt % of SiO2 and 0 to 10 wt % of Al2O3.
In this case, it is preferable that the second glass contains 15 to 35 wt % of B2O3.
Moreover, it is preferable that the second glass further contains 0.1 to 2 wt % of CuO.
While the novel features of the invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the drawings.